You could win battles easy but not the war.
The Romans were incredibly well organised. Where's your food and water coming from? Your field surgery and medication? How are you going to build artillery to break down a fort or a walled city's defences? Where are your navies? Who's going to do the navigation? Remember there's no satellites so you can't use GPS.
You got no chance winning a war with 100 trained soldiers, you need an entire army with a sophisticated command structure and with all the auxiliary defence contractors and non-combatants to do the jobs other than the fighting, jobs that are crucial to winning any war.
Your best bet in that situation is to walk to Rome, request an audience, demonstrate the power of your weapons, and then join up as the consular guard. You'd be the most high value military unit, the best paid, the one that gets all the special treatment, villas in the countryside with an ocean view and with dozens of fine hoes on deck for each of you. You'd have a great life and an easy job. But as for total power over the state, you're never getting that with just 100 guys